wget2/docs/faq.md

Wget2 FAQ (Frequently Asked Questions)

• [User Questions](#User Questions)
  • What means "Failed to connect: Wget has been built without TLS support" ?
• [Developer Questions](#Developer Questions)
  • How to do valgrind testing ?
  • How to get a test coverage report ?
  • How to enable Control Flow Integrity (CFI) with clang ?
  • How to add a new command line option ?

User Questions

Questions regarding wget2 usage

What means "Failed to connect: Wget has been built without TLS support" ?

Wget2 has been built without TLS support. You should install the gnutls development files and build again.

On Debian / Ubuntu you install those files with apt-get install gnutls-dev.

The ./configure run outputs a summary at the end. If GnuTLS has been detected, you'll see

SSL/TLS support:    yes

Developer Questions

Questions regarding building wget2, about the codebase, how to add features, ...

Please first read the short Introduction where you find basic information.

How to do valgrind testing ?

To run the complete test suite with valgrind memcheck

	make check-valgrind

or if you want valgrind memcheck by default

	./configure --enable-valgrind-tests
	make check

To run single tests with valgrind (e.g. for test-k)

	cd tests
	VALGRIND_TESTS=1 ./test-k

Why not directly using valgrind like valgrind --leak-check=full ./test-k ? Well, you want to valgrind 'wget2' and not the test program itself, right ?

Another way to run single tests with valgrind (e.g. for test-k) from the main directory

	TESTS_ENVIRONMENT="VALGRIND_TESTS=1" make check -C tests TESTS="test-k"

How to get a test coverage report ?

To generate and view the test code coverage (works with gcc, not with clang)

	make check-coverage
	xdg-open lcov/index.html

How to enable Control Flow Integrity (CFI) with clang ?

To instrument clang's CFI:

	CC="clang-5.0" CFLAGS="-g -fsanitize=cfi -fno-sanitize-trap=all -fno-sanitize=cfi-icall -flto -fvisibility=hidden" NM=/usr/bin/llvm-nm-5.0 RANLIB=/usr/bin/llvm-ranlib-5.0 AR=/usr/bin/llvm-ar-5.0 LD=/usr/bin/gold ./configure
	make clean
	make check

With clang-5.0 -fsanitize=cfi-icall does not work as expected. Our logger callback functions are typed correctly, but falsely cause a hiccup.

How to add a new command line option ?

Wget2 support many command line options, which are listed here. To add a new one:

• Extend wget_options.h/struct config with the needed variable
• Add a default value for your variable in the 'config' initializer if needed (in options.c)
• Add the long option into 'options[]' (in options.c). keep alphabetical order !
• If appropriate, add a new parse function (see examples in options.c)
• Extend the documentation (at docs/wget2.md)
• Set args to -1 if value for an option is optional

You can find more information about the option handling in Wget2 at our wiki